Oscillating restrictor

ABSTRACT

A reciprocating piston machine ( 1 ) with at least one inlet and/or outlet valve that has a strip, tongue or lamella shaped closing member ( 5 ). The opening movements ( 8 ) of the closing member ( 5 ) are limited through a stroke restrictor ( 6 ) assigned to each valve. The stroke restrictor ( 6 ) has or defines at least one ventilation hole ( 8 ) inside the contact area of the closing member ( 5 ). This ventilation hole ( 8 ) prevents the formation of air cushions ( 7 ) between the closing member ( 5 ) and the corresponding stroke restrictor ( 6 ) effectively. In the absence of the ventilation hole ( 8 ), the air cushion ( 7 ) can limit the opening movements of the closing member ( 5 ) prematurely, which in turn could lead to the generation of additional noise.

BACKGROUND

[0001] The invention relates to reciprocating piston machine with at least one inlet and/or at least one outlet valve that has a strip, tongue or lamella shaped closing member, the opening movements of which are restricted by a stroke restrictor adjacent to the valve.

[0002] Reciprocating piston machines are already known for use as compressor pumps, the inlet and outlet valves of which have a strip, tongue or lamella shaped closing member which perform the task of opening and closing the inlet/outlet openings during the pump cycle. To prevent the flexible closing member from expanding, a stroke restrictor is provided for each closing member, which limits the opening movement of the closing member. The outer contours of these stroke restrictors are regularly adapted to the outer contours of the closing members, and they are also in a strip, tongue or lamella shape.

[0003] In case of fast pump cycles however, there is the danger that an air cushion might be formed between the closing members and the corresponding stroke restrictor, which may prematurely shut the opening movement of the concerned closing member. The incomplete opening movement can result in vibration of the closing members, resulting in noise generation and an inadequate closing movement of the valve, leading to degradation of the pump's performance.

SUMMARY

[0004] The object of the invention is therefore to develop a reciprocating piston machine of the type mentioned at the above, which is characterized by a constant performance level, and especially by reduced noise generation.

[0005] The solution to this object according to the invention, in the case of reciprocating piston machines of the types mentioned earlier, is that the stroke restrictor should have at least one ventilation hole inside the contact area of the closing member.

[0006] The stroke restrictors corresponding to the inlet and/or outlet valves of the reciprocating piston machine in accordance with the invention have at least one ventilation opening inside the area of contact with the closing member. This ventilation opening prevents the unwanted formation of air cushions between the closing member and the stroke restrictors quite effectively. As the closing member is not limited prematurely in its opening position by such an air cushion, it can move back and forth between the valve seat and the stroke restrictor even in fast pump cycles. As the closing member is not exposed to natural oscillation, there is a reduction in noise generation at a performance level that is constant.

[0007] To be able to support the closing member in its opening position evenly, it is advantageous to adapt the external outline of the stroke restrictor to the external outline of the closing member. A preferred embodiment in accordance with the invention ensures that the closing member and the stroke restrictors are tongue or strip shaped.

[0008] The stroke restrictor can, for example, be made of a wire or some other similar material frame adapted to the external contours of the closing member, and it can limit the ventilation opening. However, if the stroke restrictor is made of a strip or tongue-shaped material, it can be advantageous if the stroke restrictor has at least one ventilation hole, preferably several ventilation holes with point or circle shaped hole cross sections.

[0009] In another embodiment in accordance with the invention, it is ensured that the stroke restrictor has at least one ventilation hole with a hole cross section extended in a longitudinal or crosswise direction of the stroke restrictor.

[0010] It can be advantageous if the stroke restrictor has several ventilation holes, the axes of which are aligned parallel to one another, so that they have a longitudinal hole cross section extended crosswire to the direction of the stroke restrictor.

[0011] It is especially advantageous, if the reciprocating piston machine in accordance with the invention is designed as a compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Further characteristics of the invention are evident in the following description of a preferred embodiment in accordance with the invention, in connection with the claims as well as the drawings.

[0013] The individual characteristics can be implemented singly or together in an embodiment to the invention.

[0014] In the drawings:

[0015]FIG. 1 is a partial longitudinal section of a reciprocating piston machine in the area of its inlet and outlet valves in which one stroke restrictor is assigned to each of the closing members of the valves.

[0016]FIG. 2 is a side view of the outlet valve of the reciprocating piston machine according to FIG. 1, with the closing member in the open position.

[0017]FIG. 3 is a top view of a stroke restrictor of the reciprocating piston machine according to FIGS. 1 and 2, in which the stroke restrictors in the contact area of the closing members have several circle-shaped or point-shaped ventilation holes.

[0018]FIG. 4 is a top view of a stroke restrictor with a ventilation hole that extends longitudinally along the stroke restrictor's length.

[0019]FIG. 5 is a top view of a stroke restrictor with several ventilation holes, the axes of which are aligned parallel to one another, and that are longitudinally extended in a cross direction to the length of the stroke restrictor.

[0020]FIG. 6 is a top view of a stroke restrictor without a ventilation hole, and

[0021]FIG. 7 is a side view of the stroke restrictor of FIG. 6, with the closing member in the open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] A partial longitudinal section of a reciprocating piston machine 1 is represented in FIG. 1 that serves as a pump and especially as a compressor. The pump 1 includes a pump head 2 having an inlet valve 3 and an outlet valve 4 that alternately open and close in a pump cycle. Each valve has a closing member 5 for this purpose, which moves back and forth between an open and a closed position.

[0023] A stroke restrictor 6 is provided for each valve to prevent the closing member from expanding during the opening movements.

[0024] As is clear from FIGS. 3 to 6, the external outlines of the stroke restrictors 6 are adapted to the external outlines of the closing members 5 to which they are assigned. The stroke restrictors are also designed as tongue-shaped units. The closing member 5 and the stroke restrictor 6 assigned to it are aligned on top of each other in such a way that in its open position, the closing member 5 can lie uniformly against the stroke restrictor 6.

[0025] It can be recognized from FIG. 7 that especially in fast pump cycles, an air cushion 7 may be formed between the closing member 5 and the stroke restrictor 6, which limits the opening movement of the closing member prematurely. The limited opening movements can cause the closing member to oscillate. This kind of oscillation is associated with the generation of additional noise, which can lead to undesirable efficiency losses.

[0026] It can be recognized from FIGS. 1 to 5 that one stroke restrictor is assigned to each of the valves 3, 4 of the pump. Each stroke restrictor 6 has at least one ventilation hole 8 in the contact area of the closing member 5.

[0027] This at least one ventilation hole 8 prevents the formation of undesirable air cushions between the closing member 5 and the assigned stroke restrictor 6 quite effectively. As the opening movement of the closing member 5 is not restricted by such an air cushion 7, it can move back and forth between the valve seat and the stroke restrictor 6 even in fast pump cycles. As the closing member 5 is not subjected to oscillation, generation of sound is reduced under conditions of a constant performance level of the pump.

[0028] It is recognizable in FIG. 3 that that the pump 1 illustrated in FIGS. 1 and 2 has a stroke restrictor 6 with several ventilation holes 8 with point shaped or circle shaped cross sections. These ventilation holes 8 are arranged here in two rows aligned parallel to each other along the length of the stroke restrictor.

[0029] As shown in FIG. 4 and FIG. 5, the stroke restrictor 6 can also have at least one ventilation hole 8 with a longitudinally extended hole cross section aligned lengthwise or in a cross direction to the stroke restrictor 6.

[0030] While the stroke restrictor represented in FIG. 4 has a ventilation hole 8 with a longitudinally extended hole cross section aligned along the length of the stroke restrictor 6, the stroke restrictor 6 represented in FIG. 5 has several ventilation holes 8, the axes of which are aligned parallel to one another, and that have longitudinally extended hole cross sections that are arranged crosswise to the stroke restrictor 6. 

What is claimed is:
 1. A reciprocating piston machine (1) with at least one inlet and/or at least one outlet valve (3, 4) with a strip, tongue or lamella shaped closing member (5), a stroke restrictor corresponding to the valve (3, 4) to limit opening movements of the closing member (5), wherein the stroke restrictor (6) includes or defines at least one ventilation hole (8) in a contact region of the closing member (5).
 2. A reciprocating piston machine (1) according to claim 1, wherein an external outline of the stroke restrictor (6) is complementing to an external outline of the closing member (5).
 3. A reciprocating piston machine (1) according to claim 1, wherein the stroke restrictor (6) and the closing member (5) have strip or tongue shape.
 4. A reciprocating piston machine (1) according to claim 1, wherein the stroke restrictor (6) has at least one ventilation hole (8), with a point-shaped or circular cross section.
 5. A reciprocating piston machine (1) according to claim 1, wherein the stroke restrictor (6) has at least one ventilation hole (8) with a longitudinally extended hole cross section aligned lengthwise or crosswise to the stroke restrictor (6).
 6. A reciprocating piston machine (1) according to claim 1, wherein the stroke restrictor has a plurality of ventilation holes (8) having axes which are parallel to one another, and the ventilation holes (8) have a longitudinally extended opening cross 'section that extends crosswise to the stroke restrictor (6).
 7. A reciprocating piston machine (1) according to claim 1, wherein the reciprocating piston machine (1) is a compressor.
 8. A reciprocating piston machine (1) according to claim 1, wherein the reciprocating piston machine (1) is a membrane pump. 